Maximum Daily Series Research Articles

Statistical assessment and modeling of benzene level in atmosphere in Timiş County, Romania

The aim of this article is the investigation of the benzene concentrations in the ambient air of urban and industrial areas from the Timisoara city and the rural zones of Timis County, Romania. We use the Mann–Kendall test for assessing the existence of a monotonic trend of the average and maxima daily series. Burr and Wakeby models are fit for the distributions of the average and maximum daily series collected during a period of 7 months. Based on these distributions, we compute the probabilities of exceeding the legal limits by the average daily series. These are 0.1888, 0.2159, 0.1913, and 0.1805, respectively. The highest one corresponds to the agglomerate roadside.

Trends in total precipitation and magnitude-frequency of extreme precipitation in Iran, 1969-2009

Spatiotemporal changes in total precipitation as well as the magnitude and frequency of extreme precipitation events in Iran are assessed using 187 gauging stations with at least 41 years of records until 2009. The spatial distribution of extreme precipitation is evaluated based on the generalized extreme value (GEV) distribution fitted to the annual/seasonal maximum daily series at each location. Temporal trends of the magnitude of extreme precipitation events are also analysed using the annual/seasonal maximum daily series, while temporal trends of the frequency of extremes are assessed based on records exceeding the 99th percentile threshold. Results show an overall declining trend of the annual precipitation in particular in regions located on the north, west and northwest of Iran. Seasonal analysis shows the largest contribution of winter to this declining trend. In addition, precipitation has significantly decreased in the northwest during spring. Although the changes in the magnitudes of extreme precipitation events are insignificant, with increasing trends in 50% of the stations, the overall frequencies show significant declines in particular during winter. The magnitude and frequency of extreme precipitation have also significantly declined in the northwest region during spring.